Apparatus for producing foam for fire-extinguishing purposes



H. BURMEISTER 1,749,411

APPARATUS FOR PRODUCING FOAM FOR FIRE EXTINGUISHING PURPOSES March 4,- 1930.

Filed Sept. 10, 1 927 FIEL , of the worm become gradually less while the Patented Mar. 4, 1930 vpairs!) STATES HANS BURMEISTER, F BERLIN, GERMANY, ASSIGNOR T0 PYRENE-M NIMAX COR- IPORATION, A ooBPonA'rroN OFIBELAWA E APPARATUS non PRODUCING FOAM roarmn-nxrrneu s rincrunrosns Application filed September 10, 1927, Serial No algall fi andin Ggz many Qctober My invention relates to apparatus for producing foam for fire extinguishing purposes. According to my invention the fire foam is produced by forcing powdery dry chemicals which are in conjunction with water able to form foam positively into a stream of water.

F or fire extinguishing purposes in general I it is already known to employ aworm conveyor to add certain chemicals to the water in order to impart an increased extinguishing capacity to the Water. The standard worm conveyors employed for this purpose are,

I however, unsuitable for the object in view, since it is generally necessary to convey the chemicals for foam extinguishing purposes into a stream of water standing under high pressure. In a worm conveyor of the usual construction the pressure of the water would force the chemicals back again through the worm, if the operation should be a continuous one and the chemicals were not stored in a closed container. Since, however, in my present invention continuous service must be taken into account which requires a continucm supply of the chemicals, the construction of the worm must be such that the high water pressure is notable to force the chemicals back through the worm. This end in view is, for instance, attained by making the worm and its casing of gradually diminishing diameter or tapering so that the chemicals are strongly compressedby the worm at the end adjacent to the outlet from the casing. By this compression the result is attained that the resistance of the chemicals in the worm becomes so high that the water under pressure is no longer capable of forcing the chemicals back. 7

Another possibility of attaining the same object would, for instance, be to let the pitch casing remains cylindrical. By reducing the pitch'of the worm I attain the result that during the rotation of the worm and the forward feed of the chemicals the latter become more andmore compressed between the turns of the worm and issue as a solid, compact mass from the mouth of the casing which likewise cannot be forced back through the worm by the service water.

In orderto causethe compressed chemicals the, water carries the c'he'micals" along in a state 'of 'fine' 'di'visioni In order that the water may not flow back through the windingsof the worm when jthe plant is stoppedor' che icals are no'longel' :1

fed forward, a non-return"fl'ap'j alve' or'the 'like'is preferably provided in 'the service water pipe in front oftheworm.

' Two embodiments of my'in'vention are illustrate'd in'the'drawing aflixed hereto."

In-the drawing 's'how's I F g. 1, a vertical longitudlnal section throughon'e apparatus embodying my invention, and" Fig. 2, a similar section through a modified 3 apparatus) Referring to Fig. 1 of the drawing 1) is the ipe throughwhich flows the'pres'sure water to which a're'to be added the chemicals provided in' the service pipe through which for the generation of'the foam. ,Thisftube is laterally joined' by thecasing f," in the form of a truncate'd con'e, forhousing the wormd also tapering towards the outlet from the casingand mg nte'duponthe shaft hi 1 Referring to' Fig. 2 ofth'edrawin'g 6 is again thcwa'ter pipe'and (Z the worm mounted on the shaft 72. The pitch of this worm gradually. decreases towards the outlet of the snvel ping casing which 'inftliis' case is cylindrical in a'ccordance'with the cylindrical shape of the worm."

In both designs of the apparatus a hopper a or a is mounted u'pon' the inlet 0 or c of the casing and which serves for the introduction of the chemicals into the apparatus.

The drive of the worm may be effected by a belt pulley g or g.

In front of the outlet of the worms into the water pipe I) or b is provided a non-return flap e or e. a perforated plate 2' or z" for the purpose specified.

Various changes may be made in the apparatus without departing from the spirit The pipe I) or b is fitted with of my invention and within the appended claims.- i

I claim as my invention 1. In apparatus for producing fire foam, a worm gear .for forcing the chemicals for producing the foam into a current of water under compression and subdividing means for said chemicals mounted Within the pressure water pipe.

2. In apparatus for producing fire foam, a Worm gear for forcing the chemicals for producing the foam into a current of water under compression'and adapted to compress said chemicals prior to their discharge into said current of water and subdividing means for said chemicals mounted Within the pressure water pipe. I V

3. In the apparatus for producing fire foam, atapering conveyor worm and a tapering casing enveloping said worm for forcing the chemicals for producing the foam into a current of pressure water and subdividing :means for said chemicals mounted within the pressure water pipe.

4. In apparatus for producing fire foam, a Worm gear for forcing the chemicals for producing the foam into a current of Water under compression, subdividing means for said chemicals mounted withinthe pressure water pipe, and a non-return member located between the casing of said worm and said pressure water pipe. p

5. In apparatus forproducing fire foam, a Worm gear for forcing the chemicals for producing the foam into a current of water under compression and adapted to compress said chemicals prior to the1r discharge into said current of water, subdividing means for said chemicals mounted withm'the pressure water plpe, and a non-return member located between the casing of said Worm and said pressure water pipe. 1

6. In the apparatus for producing fire foam, a tapering conveyor worm and a tapering casing enveloping said worm for, forcing the chemicals for producing the foam into a current of pressure water, subdividing means for said chemicals mounted'within the pressure water pipe, and a non-return mem-' ber located between the casing of said Worm and said pressurewater pipe. r V

I aflix my signature. r

V. HANS BURMEISTER. 

